A CRT Audio Visualiser For When LEDs Just Won’t Do

It has been a recurring feature of consumer audio gear since the first magic eye tube blinked into life, to have some kind of visualization of the sound being played. Most recently this has meant an LED array or an OLED screen, but [Thomas] has gone one better than this with a CRT television converted to perform as a rudimentary oscilloscope.

The last generation of commonly available monochrome televisions were small 5″ CRT models made in China. They never received digital tuners, so as digital TV has become the norm they are now useless to most people. Thus they can often be found for pennies on the second-hand market.

[Thomas]’s hack involves gutting such a TV and retaining its circuitry, but disconnecting the line driver from the deflection yoke. This would normally leave a vertical line on the screen as it would then be moved only by the frame driver at 50 Hz for PAL or 60 Hz for NTSC. By connecting an audio loudspeaker amplifier to the line deflection yoke he gets that low quality oscilloscope. It would be of limited use as an instrument, but few others will have such a cool audio visualizer. He’s viewing the screen in a portrait orientation, we’d be tempted to rotate the yoke for a landscape view.

It’s worth pointing out as always that CRT TVs contain high voltages, so we’d suggest reading up on how to treat them with respect.

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Screenshot from the presentation, showing the datalogger product image next to the datalogger specs stated. The specs are suspiciously similar to those of a Raspberry Pi 3.

Reclaiming A Pi-Based Solar Datalogger

There’s quite a few devices on the market that contain a Raspberry Pi as their core, and after becoming a proud owner of a solar roof, [Paolo Bonzini] has found himself with an Entrade ENR-DTLA04DN datalogger which – let’s just say, it had some of the signs, and at FOSDEM 2023, he told us all about it. Installed under the promise of local-only logging, the datalogger gave away its nature with a Raspberry Pi logo-emblazoned power brick, a spec sheet identical to that of a Pi 3, and a MAC address belonging to the Raspberry Pi Foundation. That spec sheet also mentioned a MicroSD card – which eventually died, prompting [Paolo] to take the cover off. He dumped the faulty SD card, then replaced it – and put his own SSH keys on the device while at it.

At this point, Entrade no longer offered devices with local logging, only the option of cloud logging – free, but only for five years, clearly not an option if you like your home cloud-free; the local logging was not flawless either, and thus, the device was worth exploring. A quick peek at the filesystem netted him two large statically-compiled binaries, and strace gave him a way to snoop on RS485 communications between the datalogger and the solar roof-paired inverter. Next, he dug into the binaries, collecting information on how this device did its work. Previously, he found that the device provided an undocumented API over HTTP while connected to his network, and comparing the API’s workings to the data inside the binary netted him some good results – but not enough.

The main binary was identified to be Go code, and [Paolo] shows us a walkthrough on how to reverse-engineer such binaries in radare2, with a small collection of tricks to boot – for instance, grepping the output of strings for GitHub URLs in order to find out the libraries being used. In the end, having reverse-engineered the protocol, he fully rewrote the software, without the annoying bugs of the previous one, and integrated it into his home MQTT network powered by HomeAssistant. As a bonus, he also shows us the datalogger’s main PCB, which turned out to be a peculiar creation – not to spoil the surprise!

We imagine this research isn’t just useful for when you face a similar datalogger’s death, but is also quite handy for those who find themselves at the mercy of the pseudo-free cloud logging plan and would like to opt out. Solar tech seems to be an area where Raspberry Pi boards and proprietary interfaces aren’t uncommon, which is why we see hackers reverse-engineer solar power-related devices – for instance, check out this exploration of a solar inverter’s proprietary protocol to get data out of it, or reverse-engineering an end-of-life decommissioned but perfectly healthy solar inverter’s software to get the service menu password.

Assessing The Micromirror Device From A DLP Printer For Maskless Lithography Duty

Inspired by the idea of creating a maskless lithography system using a digital micromirror device (DMD), [Nemo Andrea] tore into an Anycubic Photon Ultra, DLP & resin-based 3D printer to take a look at its projector system. Here Anycubic isn’t the maker of what is called the ‘optical engine’, which would be eViewTek’s D2 projector and its siblings. This projector assembly itself is based around the Ti DLP300s, which we covered a while back when it was brand new. Since that time Anycubic has released the Photon Ultra and Photon D2 3D printers based around these optical engines.

Using DMD for lithography isn’t a new thing, as [Nemo] points out, referencing the μMLA system by Heidelberg Systems. What would be new is using a freely available and rather affordable DMD (even if it requires sacrificing a 3D printer) to obtain its optical engine in order to create an open and more affordable lithography platform than commercial ‘contact us for a quote’ option.

No doubt it’s a challenging project, but perhaps the nice side effect of having affordable DLP 3D printers out and about is that their DMDs are now also significantly more accessible than they were previously.  We wish [Nemo] all the best in this endeavor, as a maskless lithography machine would be just that addition to any hobbyist’s toolset that we are no doubt waiting for.

(Thanks to Jerry for the tip)

Inspect The RF Realm With Augmented Reality

Intellectually, we all know that we exist in a complex soup of RF energy. Cellular, WiFi, TV, public service radio, radar, ISM-band transmissions from everything from thermometers to garage door openers — it’s all around us. It would be great to see these transmissions, but alas, most of us don’t come from the factory with the correct equipment.

Luckily, aftermarket accessories like RadioFieldAR by [Manahiyo] make it possible to visualize RF signals. As the name suggests, this is an augmented reality system that lets you inspect the RF world around you. The core of the system is a tinySA, a pocket-sized spectrum analyzer that acts as a broadband receiver. A special antenna is connected to the tinySA; unfortunately, there are no specifics on the antenna other than it needs to have a label with an image of the Earth attached to it, for antenna tracking purposes. The tinySA is connected to an Android phone — one that supports Google’s ARCore — by a USB OTG cable, and a special app on the phone runs the show.

By slowly moving the antenna around in the field of view of the phone’s camera, a heat map of signal strength at a particular frequency is slowly built up. The video below shows it in action, and the results are pretty cool. If you don’t have a tinySA, fear not — [Manahiyo] has a version of the app that supports a plain old RTL-SDR dongle too. That should make it easy for just about anyone to try this out.

And if you’re feeling deja vu about this, you’re probably remembering the [Manahiyo]’s VR spectrum analyzer, upon which this project is based.

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FDM Printing With Resin Update

[Proper Printing] is at it again. He’s trying to perfect his hybrid printer that works like an FDM printer but uses UV-curable resin gel instead of filament. You can see the latest update video below. If you missed our take on his early attempts, you might want to catch up with those earlier videos first.

The latest update brings a new nozzle, an improved light source, and changes to the formula of the resin. The nozzle and light source improvements hinge on conical lenses that convert the laser beams from a spot to a ring. The initial nozzles looked like the business end of a syringe, but this wasn’t very stable. The new video shows a conventional nozzle which also had some issues. This resulted in a custom-made nozzle that solved all the issues with the conventional nozzle and the syringe tips.

The resin formula is particularly crucial. The second attempt used resin with glass beads to give thickness. That wasn’t without problems, though, so it was switched this time with fused silica, as suggested by some comments on a previous video. They also used aggressive mixing and air removal. The consistency of the previous resins was that of a paste, but according to the video, the new mixture is more like a gel.

At some point, things started going badly. There were several equipment failures. Exasperated, he was ready to give up and was editing the video when he had an epiphany. We’re glad he didn’t give up because the new results are pretty impressive.

These printers remind us of some strange laser CNC. It also reminds us a little of people curing resin outside of the normal print process.

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ChatGPT, Bing, And The Upcoming Security Apocalypse

Most security professionals will tell you that it’s a lot easier to attack code systems than it is to defend them, and that this is especially true for large systems. The white hat’s job is to secure each and every point of contact, while the black hat’s goal is to find just one that’s insecure.

Whether black hat or white hat, it also helps a lot to know how the system works and exactly what it’s doing. When you’ve got the source code, either because it’s open-source, or because you’re working inside the company that makes the software, you’ve got a huge advantage both in finding bugs and in fixing them. In the case of closed-source software, the white hats arguably have the offsetting advantage that they at least can see the source code, and peek inside the black box, while the attackers cannot.

Still, if you look at the number of security issues raised weekly, it’s clear that even in the case of closed-source software, where the defenders should have the largest advantage, that offense is a lot easier than defense.

So now put yourself in the shoes of the poor folks who are going to try to secure large language models like ChatGPT, the new Bing, or Google’s soon-to-be-released Bard. They don’t understand their machines. Of course they know how the work inside, in the sense of cross multiplying tensors and updating weights based on training sets and so on. But because the billions of internal parameters interact in incomprehensible ways, almost all researchers refer to large language models’ inner workings as a black box.

And they haven’t even begun to consider security yet. They’re still worried about how to construct obscure background prompts that prevent their machines from spewing hate speech or pornographic novels. But as soon as the machines start doing something more interesting than just providing you plain text, the black hats will take notice, and someone will have to figure out defense.

Indeed, this week, we saw the first real shot across the bow: a hack to make Bing direct users to arbitrary (bad) webpages. The Bing hack requires the user to already be on a compromised website, so it’s maybe not very threatening, but it points out a possible real security difference between Bing and ChatGPT: Bing gives you links to follow, and that makes it a juicy target.

We’re right on the edge of a new security landscape, because even the white hats are facing a black box in the AI. So far, what ChatGPT and Codex and other large language models are doing is trivially secure – putting out plain text – but Bing is taking the first dangerous steps into doing something more useful, both for users and black hats. Given the ease with which people have undone OpenAI’s attempts to keep ChatGPT in its comfort zone, my guess is that the white hats will have their hands full, and the black-box nature of the model deprives them of their best hope. Buckle your seatbelts.

TRS-80 Model 100 Inspires Cool Cyberdeck Build, 40 Years Down The Line

The TRS-80 Model 100 was a strange beast. When it debuted in 1983, it resembled nothing that was available at the time, and filled a gap between desktop computers and the mostly-not-invented-yet laptop segment of the market. Collectors covet these machines, but they’re getting harder to find four decades later. So, if you want one, you just might have to roll your own.

Honestly, it doesn’t appear [Roberto Alsina]’s purpose here we to recreate the Model 100 per se, but rather to take inspiration from its oddball form factor and experiment with the latest components. The design elements from the original that [Roberto]’s creation most strongly echo are the screen with the extreme landscape aspect ratio and the somewhat compressed keyboard. The latter is based on the cheapest mechanical 65% keyboard available, while the former is a 1920×480 LCD display intended for automotive applications. The display seems like it put up a fight, between its need for a custom HDMI cable to connect it to the Radxa Zero SBC under the hood as well as the custom kernel needed to support it.

Along with a USB hub for IO and some 18650s for power, everything went into a 3D printed case with considerably sleeker lines than the Model 100. It’s worth pointing out that [Roberto] didn’t have much experience with design or 3D printing when he kicked off this project. We love to see people stretching their skills like that, and we think the results are great in this case. We’ve seen a lot of Model 100 retrofits and brain transplants, but this may be the first time we’ve seen a build quite like this.